Leukotriene antagonists are a new class of anti-inflammatory drugs which have shown clinical efficacy in the management of asthma. However, their role in paediatric asthma is still unclear. In essence, while there are theoretical reasons as to why leukotriene antagonists would be of use in the management of childhood asthma, there is little clinical data on their use in this patient group. Studies with leukotriene antagonists to date have been performed in children with chronic 'undertreated' asthma which, under current recommendations, should be treated with inhaled corticosteroids. Furthermore, the magnitude of effect of leukotriene antagonists on lung function (forced expiratory volume in one second of less than 5% better than placebo) and daily symptoms (0.23 puffs per day of B2 agonist less than placebo), while reaching statistical significance, is unlikely to be of clinical significance in children with chronic undertreated asthma. There is, however, good evidence for leukotriene antagonist use in exercise induced asthma in children. We conclude that although leukotriene antagonists may play an important role in the management of childhood asthma in the future, particularly as corticosteroid sparing agents and in exercise induced asthma, clinical data in paediatric asthma is poor.